Binocular Tx, Patching Boost Visual Acuity in Lazy Eye

But patching still offered superior results in kids age 5-12

Action Points

In children age 5-12 years, amblyopic-eye acuity improved with both binocular game play and fellow-eye patching, but the study could not confirm whether binocular game playing is noninferior to standard patching treatment.

Note that in participants with a good response binocular treatment worked fast, but adherence to treatment was disappointing.

In children age 5-12, amblyopic-eye acuity improved with both binocular game play and fellow-eye patching, particularly in those younger than 7 years old, according to a noninferiority study.

The 16-week mean amblyopic-eye visual acuity (VA) improved from baseline by 1.05 lines (two-sided 95% CI 0.85-1.24) in the binocular group versus 1.35 lines (two-sided 95% CI 1.17-1.54) in the patching group, for an adjusted treatment group difference of 0.31 lines in favor of patching, reported Jonathan M. Holmes, BM, BCh, of the Mayo Clinic in Rochester, Minn., and colleagues.

The upper limit of the one-sided 95% confidence interval -- 0.53 lines -- exceeded the prespecified noninferiority limit of 0.5 lines. Because of this indeterminate result, the authors were unable to establish whether binocular game playing is "not substantially worse" than standard patching treatment, they noted in JAMA Ophthalmology.

"Although the primary noninferiority analysis was indeterminate, a post-hoc analysis suggested that VA improvement with this particular binocular iPad treatment was not as good as with 2 hours of prescribed daily patching," they stated.

During 2014-2015, the 78-site trial enrolled 385 children, ages 5 to 12 years, with amblyopia (from 20/40 to 20/200, mean 20/63) as a result of strabismus, anisometropia, or both. The mean age of participants was 8.5 years, 48.6% were female, and more than 70% were white. The children were randomly assigned to either 16 weeks of a binocular iPad game prescribed for 1 hour a day and permitted to be done in segments (n=190) or patching of the fellow eye prescribed for 2 hours a day (n=195).

In binocular therapy, images are presented dichoptically, with high-contrast images offered to the amblyopic eye and low-contrast images to the fellow eye to achieve a binocular percept. This treatment has been adapted as a "falling blocks" game that uses red-green anaglyphic glasses, with initialstudies yielding promising results.

With follow-up visits scheduled at 4, 8, 12, and 16 weeks, the 16-week protocol was completed by 182 children (95.8%) in the binocular arm and 188 children (96.4%) in the patching arm.

The best results occurred in previously untreated participants younger than 7 years, with amblyopic-eye VA improving by a mean of 2.5 lines in the binocular group and 2.8 lines in the patching group. Adverse effects such as diplopia were uncommon and of similar frequency between groups.

"There has been some concern that binocular treatment might be associated with new-onset diplopia because its mechanism of action may be via antisuppression," the authors wrote. "Nevertheless, in our study and in previous studies of this particular form of binocular treatment, diplopia was rare."

The authors noted that some gaming participants lost interest in the game early and only 22% achieved greater than 75% adherence, "suggesting that adherence should be reviewed more frequently and games need to be more appealing, such as more engrossing children's games, binocular first-person action games, and binocular movie viewing."

In an invited commentary, Annegret Dahlmann-Noor, MD, PhD, of University College London's Institute of Ophthalmology described binocular treatments, as "without doubt the most exciting development in the field of amblyopia."

"For practicing ophthalmologists, this study confirms that amblyopia treatment outcomes are better in younger than in older children. Whether binocular treatments are equivalent to occlusion or atropine in young children, our main patient group, remains to be seen."

With amblyopia affecting approximately 3% of the population, more effective and child-friendly treatments are needed, she wrote. In participants with a good response, binocular treatment worked fast, with 20% achieving equal levels of contrast in both eyes within 4 weeks, and 49% experiencing that improvement in 16 weeks. "Unfortunately, it was not possible to correlate game contrast with acuity," Dahlmann-Noor wrote.

Agreeing that adherence was disappointing in this study, Dahlman-Noor added that the heterogeneous population -- with its wide range of ages, levels of neuroplasticity, types and severity of amblyopia, and inclusion of children with previous enhancing treatment -- was a major drawback. In addition, it was not clear whether children used the game as prescribed.

In her view, a smaller pilot trial may have been more appropriate to explore safety, feasibility, implementation, and adherence, and limiting risks and burdens to children and families.

"For researchers and clinician-scientists, this study is a powerful reminder that we need to involve families -- children, parents, and other caregivers -- in study design and implementation of new treatments," she wrote.

The authors also acknowledged limitations regarding the assessment of treatment adherence. For patching, the study did not use occlusion dose monitors, and adherence data relied on parental reports. Also, the electronic recording of adherence by the binocular game may have included a minimal amount of nonplaying time. In addition the binocular group was allowed to play for a minimum of 4 days per week, and reduced game play was prescribed for two children. Finally, the authors did not monitor adherence to the wearing of the red-green glasses required to play the game.

The study was funded by the National Eye Institute, the U.S. Department of Health and Human Services (HHS), Research to Prevent Blindness, the Casey Eye Institute, Wilmer Institute, Mayo Clinic, Rainbow Babies and Children's Hospital, and the University of Minnesota.

Holmes and some co-authors disclosed grants from the National Eye Institute and HHS. One co-author disclosed serving as deputy editor of JAMA Ophthalmology.

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